Boffin: Earthlike worlds within 30 lightyears of here

A heavyweight American boffin says that Earthlike worlds will soon be discovered within 30 light-years of our Solar System, and that such worlds' abundance across the universe means that the existence of alien life is a racing cert.

Speaking in advance of the American Association for the Advancement of Science annual meeting, where a major symposium on the subject took place at the weekend, Alan Boss of the Carnegie Institution laid out his view.

"There are something like a few dozen solar-type stars within something like 30 light years of the sun, and I would think that a good number of those - perhaps half of them would have Earth-like planets," he said. "So, I think there's a very good chance that we'll find some Earth-like planets within 10, 20, or 30 light years of the sun."

According to Boss, the new generation of orbital telescopes - such as the European CoRoT, which has already found a planet just twice the size of Earth, or NASA's Kepler - will be able to detect smaller, rocky planets resembling Earth. He is sure that such planets are common, and that they will be detected in our immediate stellar neighbourhood.

"I will be absolutely astonished if Kepler or COROT didn't find any earth-like planets, because basically we are finding them already," he told reporters on Saturday.

Boss believes that with Earthlike worlds so common, the emergence of life resembling that of Earth somewhere is more or less inevitable.

"I am not talking about a planet with intelligence on it. I simply say if you have a habitable world... sitting there, with the right temperature with water for a billion years, something is going to come out of it.

"At least we will have microbes," the eminent brainbox said.

In taking this view, Boss is echoing the beliefs of top-drawer British boffins who told the science minister in 2007 that alien life would be discovered soon.

Worlds where life had arisen would be apparently be relatively easy to distinguish from dead planets, owing to the presence of chemicals such as oxygen or methane in their atmospheres which could be detected by orbiting instruments just as the planets themselves will be.

"That will be pretty strong proof they are not only habitable but actually are inhabited," said Boss.

Detecting civilised life would be more difficult, he thought, partly because it was less likely to exist and partly because methods such as trying to detect radio broadcasts would be problematic and might not tell us anything.

Nonetheless, Boss thought such research was "important to do because, even though there is a small probability of success, if you actually find something, it is an immense discovery to make".